#category {
  padding: 10px;
}
#category > .panel-group {
  margin: 0;
}
#category > .panel-group > .panel {
  margin: 0;
}
#category > .panel-group > .panel > .panel-heading {
  background-color: #ebebeb;
}
#category > .panel-group > .panel > .panel-heading > .panel-title > a {
  display: block;
  position: relative;
  font-size: 18px;
  color: #000;
}
#category > .panel-group > .panel > .panel-heading > .panel-title > a:before {
  content: "";
  background-image: url('../images/arrow_up.gif');
  width: 30px;
  height: 7px;
  background-size: 30px 7px;
  background-repeat: no-repeat;
  top: 50%;
  transform: translateY(-50%);
  position: absolute;
  right: 0px;
}
#category > .panel-group > .panel > .panel-heading > .panel-title a.collapsed:before {
  background-image: url('../images/arrow_down.gif');
}
#category > .panel-group > .panel .panel-body {
  padding: 0;
}
#category > .panel-group > .panel .panel-body > .row {
  margin: 0;
}
#category > .panel-group > .panel .panel-body > .row > div {
  padding: 0;
}
#category > .panel-group > .panel .panel-body > .row > div a {
  color: #333;
  display: block;
  text-align: center;
  border: 1px solid #e6e6e6;
  border-left: 0;
  padding: 10px;
}
#category > .panel-group > .panel .panel-body > .row > div:nth-of-type(3n) a {
  border-right: 0;
}
#category > .panel-group > .panel:first-of-type {
  border-left-top: 4px;
  border-right-top: 4px;
}
#category > .panel-group > .panel:last-of-type {
  border-left-bottom: 4px;
  border-right-bottom: 4px;
}
